Permanent dielectric compositions containing photoacid generator and base

ABSTRACT

Embodiments encompassing a series of compositions containing photoacid generator (PAG) and a base are disclosed and claimed. The compositions are useful as permanent dielectric materials. More specifically, embodiments encompassing compositions containing a series of copolymers of a variety of norbornene-type cycloolefinic monomers and maleic anhydride in which maleic anhydride is fully or partially hydrolyzed (i.e., ring opened and fully or partially esterified), PAG and a base, which are useful in forming permanent dielectric materials having utility in a variety of electronic material applications, among various other uses, are disclosed.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. application Ser. No.15/364,316, filed Nov. 30, 2016, now allowed, which claims the benefitof U.S. Provisional Application No. 62/260,881, filed Nov. 30, 2015,which is incorporated herein by reference in its entirety.

TECHNICAL FIELD

The present invention relates to a series of compositions containing aphotoacid generator (PAG) and a base, which are useful as permanentdielectric materials. More specifically, the present invention relatesto compositions containing a series of copolymers of a variety ofnorbornene-type cycloolefinic monomers and maleic anhydride in whichmaleic anhydride is fully or partially hydrolyzed (i.e., ring opened andfully or partially esterified), PAG and a base, which are useful informing permanent dielectric materials having utility in a variety ofelectronic material applications, among various other uses.

BACKGROUND

As the microelectronic devices are fabricated in smaller geometriesthere is an increasing demand for advanced materials that meet thestringent requirements of confined smaller geometries. In particular,sub-micron device geometries have become common place in the fabricationof a variety of microelectronics packages for memory and logicintegrated circuits (ICs), liquid crystal displays (LCDs), organic lightemitting diodes (OLEDs) and other radio frequency (Rf) and microwavedevices. For example, devices such as radio frequency integratedcircuits (RFICs), micro-machine integrated circuits (MMICs), switches,couplers, phase shifters, surface acoustic wave (SAW) filters and SAWduplexers, have recently been fabricated with submicron dimensions.

With such smaller geometries comes a requirement for dielectricmaterials with low dielectric constants to reduce or eliminate anycross-talk between adjacent signal lines or between a signal line and adevice feature (e.g. a pixel electrode) due to capacitive coupling.Although many low dielectric (low-K) materials are available formicroelectronic devices, for optoelectronic devices such materials mustalso be broadly transparent in the visible light spectrum, not requirehigh temperature processing (greater than 300° C.) that would beincompatible with other elements of such an optoelectronic device, andbe both low-cost and feasible for large scale optoelectronic devicefabrication.

In addition, many of such applications require that such materialsfeature good thermo-mechanical properties, including low wafer stressand high elongation to break (ETB). Furthermore, the conventionalpositive tone compositions generally contain multi-functionaldiazonaphthoquinone (DNQ) photoactive compounds (PACs), which results inlower ETBs and also increase wafer stress.

Thus, it would be desirable to have a material capable of forming aself-imagable layer, which exhibits improved thermo-mechanicalproperties. Such material should also be easy to apply to a substrate,have a low dielectric constant (3.9 or less) and thermal stability totemperatures in excess of 250° C. Of course, it is also desirable tohave such materials available at a lower cost and feature suchproperties as positive photoimaging capability, aqueous base developingcapability, high transparency after heat stress and low weight loss atcuring temperatures. It has been reported that acrylic polymers, whichare inexpensive, offer good photoimaging properties and are aqueous basedevelopable, see for example, Japanese Patent Application Laid-open No.Hei 5-165214 and the radiation-sensitive resin composition comprising analicyclic olefin resin disclosed in Japanese Patent ApplicationLaid-open No. 2003-162054. Similarly, polyimides have been reported toprovide good thermal stability. However, these materials have certaindeficiencies and thus making them not so suitable for the applicationscontemplated herein. For instance, acrylics are not suitable forapplications requiring high thermal stability (i.e., temperatures higherthan 200° C.), and many of the polyimides in general are not suitablefor either positive tone or negative tone formulations requiring aqueousbase developability and generally do not exhibit desirable transparency,thus making them unsuitable in certain optoelectronic applications.Although some polyimides and polybenzoxazoles have low dielectricconstants but still may not have low enough permittivity to be effectivein highly integrated and/or miniaturized devices having increased wiringdensity and high signal speed. Furthermore, both polyimides andpolybenzoxazoles require cure temperatures in excess of 300° C., thusrendering them unsuitable for many applications. One such knownpolyimide material is the positive tone photosensitive resin comprisinga polyimide precursor and a diazoquinone-type compound disclosed inJapanese Patent No. 3,262,108.

Recently, it has been reported that certain copolymers containingnorbornene-type repeat units having pendent maleimide groups and maleicanhydride-type repeat units are useful in certain microelectronicapplications featuring self-image forming layer capability, whenimage-wise-exposed to actinic radiation, see co-pending U.S. patentapplication Ser. No. 14/034,682, filed Sep. 24, 2013.

However, there is still a need for cost effective permanent dielectricmaterials having not only self photopatternable properties but alsocontaining no DNQ-type PACs, yet exhibiting good properties, includingimproved thermo-mechanical properties, retaining film thickness from theunexposed regions of a positive tone formulation (i.e., low dark fieldloss), low thermal reflow after cure, improved stability to variouschemicals and process conditions involved in the downstream processfabrication steps, such as, for example, in a device containing aredistribution layer (RDL), and/or solvent stripper operations, amongothers.

Thus it is an object of this invention to provide organic polymermaterials having aforementioned properties for a variety of electronicand/or optoelectronic device fabrication applications.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments in accordance with the present invention are described belowwith reference to the following accompanying figures and/or images.Where drawings are provided, it will be drawings which are simplifiedportions of a device provided for illustrative purposes only.

FIG. 1 shows FT-IR spectra of two different composition embodiments ofthis invention as further discussed herein.

FIG. 2A and FIG. 2B show cross section scanning electron micrographs(SEM) of a positive tone lithographic images of 5 μm (FIG. 2A) and 10 μmisolated trenches (FIG. 2B) at an exposure dose of 255 mJ/cm² of one ofthe photosensitive composition embodiments of this invention.

FIG. 3 shows cross section scanning electron micrograph (SEM) of apositive tone lithographic images of 10 μm isolated trenches at anexposure dose of 283 mJ/cm² of one of the photosensitive compositionembodiments of this invention.

FIG. 4A and FIG. 4B show cross section scanning electron micrographs(SEM) of a positive tone lithographic images of 25 μm contact holesbefore cure (FIG. 4A) and after cure (FIG. 4B) of one of thephotosensitive composition embodiments of this invention.

DETAILED DESCRIPTION

Embodiments in accordance with the present invention are directed tovarious polymers, including but not limited to, polymers that encompassat least one repeating unit derived from a certain type ofnorbornene-type monomer as described herein, at least one secondrepeating unit derived from a maleic anhydride-type monomer, as such aredefined hereinafter and at least one third repeating unit derived from amaleimide, and to compositions encompassing such polymers. Such polymercompositions being capable of forming self-imagable films useful aslayers in the manufacture of microelectronic and optoelectronic devices.That is to say that, after image-wise exposure to actinic radiation,such layers (or films) can be developed to form patterned layers (orfilms), where such pattern is reflective of the image through which thelayers (or films) was exposed. In this manner, structures can beprovided that are, or are to become, a part of such microelectronicand/or optoelectronic devices.

The terms as used herein have the following meanings:

As used herein, the articles “a,” “an,” and “the” include pluralreferents unless otherwise expressly and unequivocally limited to onereferent.

Since all numbers, values and/or expressions referring to quantities ofingredients, reaction conditions, etc., used herein and in the claimsappended hereto, are subject to the various uncertainties of measurementencountered in obtaining such values, unless otherwise indicated, allare to be understood as modified in all instances by the term “about.”

Where a numerical range is disclosed herein such range is continuous,inclusive of both the minimum and maximum values of the range as well asevery value between such minimum and maximum values. Still further,where a range refers to integers, every integer between the minimum andmaximum values of such range is included. In addition, where multipleranges are provided to describe a feature or characteristic, such rangescan be combined. That is to say that, unless otherwise indicated, allranges disclosed herein are to be understood to encompass any and allsub-ranges subsumed therein. For example, a stated range of from “1 to10” should be considered to include any and all sub-ranges between theminimum value of 1 and the maximum value of 10. Exemplary sub-ranges ofthe range 1 to 10 include, but are not limited to, 1 to 6.1, 3.5 to 7.8,and 5.5 to 10, etc.

As used herein, the symbol “

” denotes a position at which the bonding takes place with anotherrepeat unit or another atom or molecule or group or moiety asappropriate with the structure of the group as shown.

As used herein, “hydrocarbyl” refers to a radical of a group thatcontains carbon and hydrogen atoms, non-limiting examples being alkyl,cycloalkyl, aryl, aralkyl, alkaryl, and alkenyl. The term“halohydrocarbyl” refers to a hydrocarbyl group where at least onehydrogen has been replaced by a halogen. The term perhalocarbyl refersto a hydrocarbyl group where all hydrogens have been replaced by ahalogen.

As used herein, the expression “(C₁-C₁₅)alkyl” includes methyl and ethylgroups, and straight-chained or branched propyl, butyl, pentyl, hexyl,heptyl, and various other homolog groups. Particular alkyl groups aremethyl, ethyl, n-propyl, isopropyl and tert-butyl, etc. Derivedexpressions, such as “(C₁-C₁₅)alkoxy”, “(C₁-C₁₅)thioalkyl”“(C₁-C₁₅)alkoxy(C₁-C₁₅)alkyl”, “hydroxy(C₁-C₁₅)alkyl”,“(C₁-C₁₅)alkylcarbonyl”, “(C₁-C₁₅)alkoxycarbonyl(C₁-C₁₅)alkyl”,“(C₁-C₁₅)alkoxycarbonyl”, “amino(C₁-C₁₅)alkyl”, “(C₁-C₁₅)alkylamino”,“(C₁-C₁₅)alkylcarbamoyl(C₁-C₁₅)alkyl”,“(C₁-C₁₅)dialkylcarbamoyl(C₁-C₁₅)alkyl” “mono- ordi-(C₁-C₁₅)alkylamino(C₁-C₁₅)alkyl”, “amino(C₁-C₁₅)alkylcarbonyl”“diphenyl(C₁-C₁₅)alkyl”, “phenyl(C₁-C₁₅)alkyl”,“phenylcarbonyl(C₁-C₁₅)alkyl” and “phenoxy(C₁-C₁₅)alkyl” are to beconstrued accordingly.

As used herein, the expression “cycloalkyl” includes all of the knowncyclic radicals. Representative examples of “cycloalkyl” includeswithout any limitation cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl,cycloheptyl, cyclooctyl, and the like. Derived expressions such as“cycloalkoxy”, “cycloalkylalkyl”, “cycloalkylaryl”, “cycloalkylcarbonyl”are to be construed accordingly.

As used herein, the expression “(C₂-C₆)alkenyl” includes ethenyl andstraight-chained or branched propenyl, butenyl, pentenyl and hexenylgroups. Similarly, the expression “(C₂-C₆)alkynyl” includes ethynyl andpropynyl, and straight-chained or branched butynyl, pentynyl and hexynylgroups.

As used herein the expression “(C₁-C₄)acyl” shall have the same meaningas “(C₁-C₄)alkanoyl”, which can also be represented structurally as“R—CO—,” where R is a (C₁-C₃)alkyl as defined herein. Additionally,“(C₁-C₃)alkylcarbonyl” shall mean same as (C₁-C₄)acyl. Specifically,“(C₁-C₄)acyl” shall mean formyl, acetyl or ethanoyl, propanoyl,n-butanoyl, etc. Derived expressions such as “(C₁-C₄)acyloxy” and“(C₁-C₄)acyloxyalkyl” are to be construed accordingly.

As used herein, the expression “(C₁-C₁₅)perfluoroalkyl” means that allof the hydrogen atoms in said alkyl group are replaced with fluorineatoms. Illustrative examples include trifluoromethyl andpentafluoroethyl, and straight-chained or branched heptafluoropropyl,nonafluorobutyl, undecafluoropentyl and tridecafluorohexyl groups.Derived expression, “(C₁-C₁₅)perfluoroalkoxy”, is to be construedaccordingly.

As used herein, the expression “(C₆-C₁₀)aryl” means substituted orunsubstituted phenyl or naphthyl. Specific examples of substitutedphenyl or naphthyl include o-, p-, m-tolyl, 1,2-, 1,3-, 1,4-xylyl,1-methylnaphthyl, 2-methylnaphthyl, etc. “Substituted phenyl” or“substituted naphthyl” also include any of the possible substituents asfurther defined herein or one known in the art. Derived expression,“(C₆-C₁₀)arylsulfonyl,” is to be construed accordingly.

As used herein, the expression “(C₆-C₁₀)aryl(C₁-C₄)alkyl” means that the(C₆-C₁₀)aryl as defined herein is further attached to (C₁-C₄)alkyl asdefined herein. Representative examples include benzyl, phenylethyl,2-phenylpropyl, 1-naphthylmethyl, 2-naphthylmethyl and the like.

As used herein, the expression “heteroaryl” includes all of the knownheteroatom containing aromatic radicals. Representative 5-memberedheteroaryl radicals include furanyl, thienyl or thiophenyl, pyrrolyl,isopyrrolyl, pyrazolyl, imidazolyl, oxazolyl, thiazolyl, isothiazolyl,and the like. Representative 6-membered heteroaryl radicals includepyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, triazinyl, and the likeradicals. Representative examples of bicyclic heteroaryl radicalsinclude, benzofuranyl, benzothiophenyl, indolyl, quinolinyl,isoquinolinyl, cinnolyl, benzimidazolyl, indazolyl, pyridofuranyl,pyridothienyl, and the like radicals.

As used herein, the expression “heterocycle” includes all of the knownreduced heteroatom containing cyclic radicals. Representative 5-memberedheterocycle radicals include tetrahydrofuranyl, tetrahydrothiophenyl,pyrrolidinyl, 2-thiazolinyl, tetrahydrothiazolyl, tetrahydrooxazolyl,and the like. Representative 6-membered heterocycle radicals includepiperidinyl, piperazinyl, morpholinyl, thiomorpholinyl, and the like.Various other heterocycle radicals include, without limitation,aziridinyl, azepanyl, diazepanyl, diazabicyclo[2.2.1]hept-2-yl, andtriazocanyl, and the like.

“Halogen” or “halo” means chloro, fluoro, bromo, and iodo.

In a broad sense, the term “substituted” is contemplated to include allpermissible substituents of organic compounds. In a few of the specificembodiments as disclosed herein, the term “substituted” meanssubstituted with one or more substituents independently selected fromthe group consisting of (C₁-C₆)alkyl, (C₂-C₆)alkenyl,(C₁-C₆)perfluoroalkyl, phenyl, hydroxy, —CO₂H, an ester, an amide,(C₁-C₆)alkoxy, (C₁-C₆)thioalkyl, (C₁-C₆)perfluoroalkoxy, —NH₂, Cl , Br,I, F, —NH(C₁-C₆)alkyl, and —N((C₁-C₆)alkyl)₂. However, any of the othersuitable substituents known to one skilled in the art can also be usedin these embodiments.

The statements below, wherein, for example, R₅ and R₆ are said to beindependently selected from a group of substituents, means that R₅ andR₆ are independently selected, but also that where an R₅ variable occursmore than once in a molecule, those occurrences are independentlyselected (e.g., if R₁ and R₂ are each contains a group of formula (A),R₅ can be hydrogen in R₁, and R₅ can be methyl in R₂). Those skilled inthe art will recognize that the size and nature of the substituent(s)can affect the number and nature of other substituents that can bepresent.

It should be noted that any atom with unsatisfied valences in the text,schemes, examples and tables herein is assumed to have the appropriatenumber of hydrogen atom(s) to satisfy such valences.

As used herein, the terms “polymer composition,” or “terpolymercomposition” are used herein interchangeably and are meant to include atleast one synthesized polymer or terpolymer, as well as residues frominitiators, solvents or other elements attendant to the synthesis ofsuch polymers, where such residues are understood as not beingcovalently incorporated thereto. Such residues and other elementsconsidered as part of the “polymer” or “polymer composition” aretypically mixed or co-mingled with the polymer such that they tend toremain therewith when it is transferred between vessels or betweensolvent or dispersion media. A polymer composition can also includematerials added after synthesis of the polymer to provide or modifyspecific properties of such composition. Such materials include, but arenot limited to solvent(s), antioxidant(s), photoinitiator(s),sensitizers and other materials as will be discussed more fully below.

By the term “derived” is meant that the polymeric repeating units arepolymerized (formed) from, e.g., polycyclic norbornene-type monomers, inaccordance with formula (I) and maleic anhydride monomers of formula(II), wherein the resulting polymers are formed by 2,3 enchainment ofnorbornene-type monomers with maleic anhydride monomers in analternating fashion as shown below:

It should be understood that depending upon the monomeric compositionsin a given polymer the repeat units may not always be alternating. Thatis to say, for example, in a polymer containing other than 50:50 molarratios of norbornene-type monomers with combined molar amounts of maleicanhydride and maleimide monomers, the repeat units are not alwaysalternating but with random blocks of monomers with the higher molarcontent.

The term “low K” refers in general to a dielectric constant less thanthat of thermally formed silicon dioxide (3.9) and when used inreference to a “low-K material” it will be understood to mean a materialhaving a dielectric constant of less than 3.9.

The term “photodefinable” refers to the characteristic of a material orcomposition of materials, such as a polymer composition in accordancewith embodiments of the present invention, to be formed into, in and ofitself, a patterned layer or a structure. In alternate language, a“photodefinable layer” does not require the use of another materiallayer formed thereover, for example a photoresist layer, to form theaforementioned patterned layer or structure. It will be furtherunderstood that a polymer composition having such a characteristic beemployed in a pattern forming scheme to form a patterned film/layer orstructure. It will be noted that such a scheme incorporates an“imagewise exposure” of the photodefinable material or layer. Suchimagewise exposure being taken to mean an exposure to actinic radiationof selected portions of the layer, where non-selected portions areprotected from such exposure to actinic radiation.

The phrase “a material that photonically forms a catalyst” refers to amaterial that, when exposed to “actinic radiation” will break down,decompose, or in some other way alter its molecular composition to forma compound capable of initiating a crosslinking reaction in the polymer,where the term “actinic radiation” is meant to include any type ofradiation capable of causing the aforementioned change in molecularcomposition. For example, any wavelength of ultraviolet or visibleradiation regardless of the source of such radiation or radiation froman appropriate X-ray and electron beam source. Non-limiting examples ofsuitable materials that “photonically form catalyst” include photoacidgenerators and photobase generators such as are discussed in detailbelow. It should also be noted that generally “a material thatphotonically forms a catalyst” will also form a catalyst if heated to anappropriate temperature. Such exposures are sometimes desirable afterdeveloping a positive tone image and to fix the images post developingby blanket exposure to a suitable radiation.

The term “cure” (or “curing”) as used in connection with a composition,e.g., “a cured composition,” shall mean that at least a portion of thecrosslinkable components which are encompassed by the composition are atleast partially crosslinked. In some embodiments of the presentinvention, the crosslinking is sufficient to render the polymer filminsoluble in the developer and in some other embodiments the polymerfilm is insoluble in commonly used solvents. One skilled in the art willunderstand that the presence and degree of crosslinking (crosslinkdensity) can be determined by a variety of methods, such as dynamicmechanical thermal analysis (DMTA). This method determines the glasstransition temperature and crosslink density of free films of coatingsor polymers. These physical properties of a cured material are relatedto the structure of the crosslinked network. Higher crosslink densityvalues indicate a higher degree of crosslinking in the coating or film.

Monomers

Various first type of monomers as described herein which are part ofpolymer embodiments in accordance with the present invention aregenerally known in the art. In general, the polymers of this inventionencompass a wide range of first type of “polycyclic” repeating units. Asdefined herein, the terms “polycyclic olefin” or “polycycloolefin” meanthe same and are used interchangeably to represent several of the firsttype of monomeric compounds used to prepare the polymers of thisinvention. As a representative example of such a compound or a monomeris “norbornene-type” monomer and is generally referred to herein asaddition polymerizable monomer (or the resulting repeating unit), thatencompass at least one norbornene moiety such as shown below:

The simplest norbornene-type or polycyclic olefin monomer encompassed byembodiments in accordance with the present invention is norborneneitself, also known as bicyclo[2.2.1]hept-2-ene. However, the termnorbornene-type monomer or repeating unit is used herein to meannorbornene itself as well as any substituted norbornene(s), orsubstituted and unsubstituted higher cyclic derivatives thereof.Representative examples of such monomers include but not limited tobicyclo[2.2.2]oct-2-ene,1,2,3,4,4a,5,8,8a-octahydro-1,4:5,8-dimethanonaphthalene,1,4,4a,5,6,7,8,8a-octahydro-1,4-epoxy-5,8-methanonaphthalene, and thelike.

As mentioned above, the “norbornene-type” monomeric compounds employedin this invention can be synthesized by any of the procedures known toone skilled in the art. Specifically, several of the starting materialsused in the preparation of the first type of monomers used herein areknown or are themselves commercially available. The first type ofmonomers employed herein as well as several of the precursor compoundsmay also be prepared by methods used to prepare similar compounds asreported in the literature and as further described herein. See forinstance, U.S. Patent Application No. US2012/0056183 A1.

In general, an economical route for the preparation of first type ofmonomers of formula (I), wherein m=0, relies on the Diels-Alder additionreaction in which cyclopentadiene (CPD, IV) is reacted with a suitabledienophile of formula (V) or (VI) at suitable reaction temperatureswhich are typically at elevated temperatures to form the monomers offormula (I) or (III) generally shown by the following reaction scheme I:

Wherein R₁, R₂, R₃ and R₄ are as defined herein.

Other monomeric compounds of formula (I), wherein m=1 or 2 can also beprepared similarly by the thermolysis of dicyclopentadiene (DCPD, VI) inthe presence of a suitable dienophile of formula (V). In this approach,the compound of formula (I) formed itself acts as a dienophile andreacts with CPD, IV to give a compound of formula (I), where m=1, whichcan again be reacted with another molecule of CPD, IV to forma acompound of formula (I), where m=2, and so on, as shown in Scheme II:

Wherein m, R₁, R₂, R₃ and R₄ are as defined herein. The dienophile offormula (V) are either generally available commercially or can beprepared following any of the known literature procedures.

Similarly, various other monomers of formulae (II) as described hereinare also known in the art or are themselves commercially available.Also, monomers of formulae (II) can be synthesized by any of theprocedures known to one skilled in the art.

Polymers

Embodiments in accordance with the present invention encompass polymershaving at least one repeating unit derived from a norbornene-typemonomer of formula (I) as defined herein, and at least one repeatingunit derived from a maleic anhydride-type monomer of formula (II) asdefined herein. It should be understood that various other types ofmonomers can also be used in addition to monomers of formulae (I) and(II) to form the polymers employed in this invention. Such polymers canbe prepared by any of the methods known in the art. Generally, suchpolymers are prepared by free radical polymerization methods. See forexample, U.S. Pat. No. 8,715,900, which discloses ring-opened maleicanhydride polymers with alcohols (ROMA) and copolymerized with a varietyof norbornene monomers as described herein, pertinent portions of whichare incorporated herein by reference. Various other methods, such as forexample, vinyl addition polymerization using transition metal catalysts,such as for example, nickel or palladium can also be employed to makecertain of the polymers employed to make the photoimagable compositionsof this invention.

Photoimagable Compositions

Thus, in accordance with the practice of this invention there isprovided a composition comprising:

a polymer comprising one or more distinct first repeating unitrepresented by formula (IA), each of said first repeating unit isderived from a monomer of formula (I):

wherein:

represents a position at which the bonding takes place with anotherrepeat unit;

m is an integer 0, 1 or 2;

R₁, R₂, R₃ and R₄ independently represents hydrogen, linear or branched(C₁-C₁₆)alkyl, hydroxy(C₁-C₁₂)alkyl, perfluoro(C₁-C₁₂)alkyl,(C₃-C₁₂)cycloalkyl, (C₆-C₁₂)bicycloalkyl, (C₇-C₁₄)tricycloalkyl,(C₆-C₁₀)aryl, (C₆-C₁₀)aryl(C₁-C₃)alkyl, perfluoro(C₆-C₁₀)aryl,perfluoro(C₆-C₁₀)aryl(C₁-C₃)alkyl, (C₅-C₁₀)heteroaryl,(C₅-C₁₀)heteroaryl(C₁-C₃)alkyl, hydroxy, (C₁-C₁₂)alkoxy,(C₃-C₁₂)cycloalkoxy, (C₆-C₁₂)bicycloalkoxy, (C₇-C₁₄)tricycloalkoxy,—(CH₂)_(a)—(O—(CH₂)_(b))_(c)—O—(C₁-C₄)alkyl, where a, b and c areintegers from 1 to 4, (C₆-C₁₀)aryloxy(C₁-C₃)alkyl,(C₅-C₁₀)heteroaryloxy(C₁-C₃)alkyl, (C₆-C₁₀)aryloxy,(C₅-C₁₀)heteroaryloxy, (C₁-C₆)acyloxy and halogen; and

a second repeating unit represented by formula (IIA), said secondrepeating unit is derived from a monomer of formula (II):

wherein:

R₅, R₆, R₇ and R₈ are each independently of one another hydrogen orlinear or branched (C₁-C₉)alkyl, fluorinated orperfluorinated(C₁-C₉)alkyl, (C₁-C₁₂)alkoxy(C₁-C₁₂)alkyl and(C₁-C₁₂)alkoxy(C₁-C₁₂)alkoxy(C₁-C₁₂)alkyl;

a photoacid generator;

a base; and

a carrier solvent.

As noted, the polymers of this invention generally encompasses at leastone monomer each of formulae (I) and (II). However, the polymer of thisinvention can encompass more than one monomer of formulae (I) distinctfrom one another. Similarly, more than one distinct monomer of formula(II) can also be used. Thus, the polymers used to form thephotosensitive or photoimagable compositions of this invention can be acopolymer containing at least one monomer of formula (I) and one monomerof formula (II); a terpolymer containing at least one monomer each offormulae (I) and (II), and an additional distinct monomer selectedeither from formulae (I) or (II); a tetrapolymer containing at least onemonomer each of formulae (I) and (II), and two additional distinctmonomers selected from formulae (I) and/or (II); and so on. All suchvarious combinations are part of this invention. Accordingly, in one ofthe embodiments of this invention, the composition of this inventionencompasses a copolymer having one monomer each of formulae (I) and(II). In another embodiment of this invention, the composition of thisinvention encompasses a terpolymer having two distinct repeat unitsderived from two different monomers of formula (I) and one repeat unitderived from a monomer of formula (II). In yet another embodiment ofthis invention, the composition of this invention encompasses atetrapolymer having three distinct repeat units derived from threedifferent monomers of formula (I) and one repeat unit derived from amonomer of formula (II); or a tetrapolymer having two distinct repeatunits derived from two different monomers of formula (I) and twodistinct repeat units derived from two different monomers of formula(II).

In another embodiment, the composition of this invention encompasses apolymer, which further comprises a second distinct repeat unit offormula (IIB) derived from a monomer of formula (II):

wherein R₅ and R₆ are as defined hereinabove.

In another embodiment, the composition of this invention encompasses apolymer, which comprises one or more distinct repeating units of formula(IA) having:

m is 0;

R₁, R₂, R₃ and R₄ are independently selected from the group consistingof hydrogen, methyl, ethyl, linear or branched (C₁-C₁₂)alkyl,phenyl(C₁-C₃)alkyl, —(CH₂)_(a)—(O—(CH₂)_(b))_(c)—O—(C₁-C₄)alkyl, where ais 1 or 2, b is 2 to 4 and c is 2 or 3.

In another embodiment, the composition of this invention encompasses apolymer having R₅ and R₆ independently of each other selected fromhydrogen and methyl; and each R₇ and R₈ independently of one anotherselected from hydrogen, methyl, ethyl, n-propyl and n-butyl.

Useful monomers for embodiments in accordance with the present inventionare described generally herein and are further described by the monomerand substituent structures provided herein. It should further be notedthat the polymer of this invention generally encompasses equal molaramounts of repeat units derived from one or more monomers of formula (I)and repeat units derived from one or more monomers of formula (II). Thatis to say that the total molar amounts of one or more distinct types ofmonomers of formula (I) and the total molar amounts of one or moredistinct types of monomers of formula (II) are generally the same. Inthis regard, the two distinct types of repeat units of formulae (IA),(IIA) or (IIB), if present, in the back bone of the polymer may bemostly alternating with norbornene-type repeating unit of formula (I)with one of maleic-anhydride repeat unit of formula (IIA) or (IIB).However, such repeat units of formulae (IA), (IIA) or (IIB) may also berandomly arranged or may form blocks, all such forms of polymers arepart of this invention. In some embodiments, the norbornene-type repeatunits are mostly alternating with the maleic-anhydride type repeatunits. In other embodiments, such polymer compositions can encompass apolymer containing two or more distinct types of norbornene-typerepeating units and at least one maleic anhydride-type repeating unit,or a polymer containing at least one norbornene-type repeating unit andtwo or more distinct types of maleic anhydride repeating units asfurther described herein.

Generally speaking, as to various possible substituents defined for R₁,R₂, R₃, R₄, it should be noted that such substituents can broadly bedefined as “hydrocarbyl” group. As defined hereinabove, such definitionof“hydrocarbyl” group includes any C₁ to C₃₀ alkyl, aryl, aralkyl,alkaryl, cycloalkyl, or heteroalkyl group. Representative alkyl groupsinclude, but are not limited to, methyl, ethyl, propyl, isopropyl,butyl, isobutyl, sec-butyl, tert-butyl, pentyl, neopentyl, hexyl,heptyl, octyl, nonyl, and decyl. Representative cycloalkyl groupsinclude, but are not limited to, adamantyl, cyclopentyl, cyclohexyl, andcyclooctyl. Representative aryl groups include, but are not limited to,phenyl, naphthyl, and anthracenyl. Representative aralkyl groupsinclude, but are not limited to, benzyl and phenethyl. In addition, itshould be noted that the hydrocarbyl groups mentioned above can besubstituted, that is to say at least one of the hydrogen atoms can bereplaced with, for example, (C₁-C₁₀)alkyl, haloalkyl, perhaloalkyl,aryl, and/or cycloalkyl group(s). Representative substituted cycloalkylgroups include, among others, 4-t-butylcyclohexyl and2-methyl-2-adamantyl. A non-limiting representative substituted arylgroup is 4-t-butylphenyl.

Various types of norbornene-type monomers of formula (I) can be employedin order to form the polymers of this invention which contain the firstrepeat units derived therefrom. More specifically, any of the knownnorbornene-type monomers of formula (I) can be employed. For example,various such monomers are disclosed in U.S. Patent Publication No. US2012/0056183 A1. Exemplary monomers which form such first repeating unitinclude but not limited to those monomers selected from the groupconsisting of:

Accordingly, in one of the embodiments, the composition of thisinvention encompasses a polymer having one or more first repeating uniteach of which is derived from a corresponding monomer selected from thegroup consisting of:

-   5-hexylbicyclo[2.2.1]hept-2-ene;-   5-octylbicyclo[2.2.1]hept-2-ene;-   5-decylbicyclo[2.2.1]hept-2-ene;-   5-((2-(2-methoxyethoxy)ethoxy)methyl)bicyclo[2.2.1]hept-2-ene;-   1-(bicyclo[2.2.1]hept-5-en-2-yl)-2,5,8,11-tetraoxadodecane;-   5-benzylbicyclo[2.2.1]hept-2-ene; and-   5-phenethylbicyclo[2.2.1]hept-2-ene.

Turning now to second repeating unit to form the polymer of thisinvention it is contemplated that any maleic anhydride derivative can beused as a monomer, including maleic anhydride itself. Exemplary monomersof such type include but not limited to those selected from the groupconsisting of:

In another embodiment, the composition of this invention encompasses apolymer having one or more second repeating unit each of which isderived from a corresponding monomer selected from the group consistingof:

-   maleic anhydride;-   2-methyl-maleic anhydride (3-methylfuran-2,5-dione);-   2,3-dimethyl-maleic anhydride (3,4-dimethylfuran-2,5-dione);-   2-ethyl-maleic anhydride (3-ethylfuran-2,5-dione);-   2,3-diethyl-maleic anhydride (3,4-diethylfuran-2,5-dione);-   2-trifluoromethyl-maleic anhydride    (3-trifluoromethylfuran-2,5-dione);-   2,3-bis(trifluoromethyl)-maleic anhydride    (3,4-bis(trifluoromethyl)furan-2,5-dione); and-   2-methyl-3-trifluoromethyl-maleic anhydride    (3-methyl-4-(trifluoromethyl)furan-2,5-dione).

Advantageously, as noted above, it has now been found that the polymersemployed in this invention feature an alternating sequence of one ormore of first type of repeat units of formulae (IA) with one or morerepeat units of maleic anhydride of formulae (IIA) or (IIB),particularly if the polymer is made by a free radical polymerization asdescribed herein. Thus, the polymers of this invention generallyincorporate repeating units of formula (IA) from about 40 mole percentto about 60 mole percent. The remaining repeat units are being derivedfrom a combination of repeat units of formulae (IIA) and (IIB).

Again, as noted above, one or more distinct types of repeat units offormula (IA) may be present in the polymer of this invention.Accordingly, in one of the embodiments the polymer of this inventioncontains only one type of repeat unit of formula (IA). In anotherembodiment, the polymer of this invention contains two distinctive typesof repeat units of formula (IA). In other embodiments the polymer ofthis invention contains more than two distinctive types of repeat unitsof formula (IA). Similarly, various different types of repeat units offormulae (IIA) and (IIB) can be used to form the polymers of thisinvention.

As noted, the polymer as obtained above is then subjected to suitablereaction conditions to ring open the maleic anhydride repeat units offormula (IIB), the ROMA polymers employed in the compositions of thisinvention. Any of the known methods which would bring about such a ringopening can be employed in this method of the invention. Non-limitingexamples of such ring opening reactions include reacting the polymerwith a suitable alcohol optionally in the presence of a suitable base oran acid. Non-limiting examples of alcohols include methanol, ethanol,n-propanol, iso-propanol, n-butanol, iso-butanol, tert-butanol,pentanol, hexanol, octanol, fluoroalkanol, methoxyethanol,methoxyethoxymethanol, methoxyethoxyethanol, and the like. Non-limitingexamples of base include sodium hydroxide, lithium hydroxide, potassiumhydroxide, cesium hydroxide, ammonia, ammonium hydroxide, magnesiumhydroxide, calcium hydroxide, barium hydroxide, and the like. Variousother known organic bases can also be employed. Representative examplesof which include, tetramethylammonium hydroxide (TMAH),tetraethylammonium hydroxide (TEAH), pyridine, imidazole, and the like.Non-limiting examples of acids include acetic acid, trifluoroaceticacid, sulfuric acid, hydrochloric acid, methanesulfonic acid,trifluoromethanesulfonic acid, p-toluenesulfonic acid, benzenesulfonicacid, and mixtures thereof. As noted, in some embodiments the ringopening can also be carried without any acid or base.

The aforementioned ring opening reactions can be carried out using anyof the known methods in the art. Typically, such reactions are carriedout in a suitable solvent or a mixture of solvents in the presence of abase and an alcohol. Examples of base and alcohol are already describedabove. Non-limiting examples of solvents include tetrahydrofuran (THF),acetonitrile, dimethylacetamide (DMAc), dimethyl sulfoxide (DMSO),N-methylpyrrolidone (NMP), propyleneglycol monomethylether acetate(PGMEA), ethyl acetate, methyl ethyl ketone (MEK), toluene, hexane,water, and mixtures thereof. The reaction can be carried out at suitabletemperature including ambient, sub-ambient and super-ambient conditions.Typically, the reaction temperature employed is in the range of about 40to 90° C. and in certain embodiments the temperature can be in the rangeof 50 to 80° C. and in some other embodiments it can be in the range of60 to 70° C.

The ROMA polymers so formed in accordance with this invention, dependingupon contacting with such aforementioned reagents will cause eithercomplete or partial ring open of the maleic anhydride repeating units toform a repeat unit of formula (IIA). Thus, such ROMA polymers may have arandomly ordered repeat units of formula (IA), (IIA) and (IIB), whereinthe repeat units of formula (IIA) may include a combination of diacid(i.e., both R₇ and R₈ are hydrogen), monoester (i.e., one of R₇ and R₈is hydrogen) or a diester (i.e., both R₇ and R₈ are alkyl, and the like)depending upon the degree of esterification with the alcohol. Thus inaccordance with this aspect of the embodiment of this invention, thering opened portion of the maleic anhydride repeat unit of formula (IIA)is in the order of from about 1 mole percent to about 100 mole percent;in some other embodiments it is higher than 40 mole percent; in someother embodiments it is higher than 60 mole percent; and in some otherembodiments it is higher than 80 mole percent. In some other embodimentsmore than 90 mole percent of maleic anhydride units are ring openedwhere one of R₇ and R₈ is hydrogen. That is, the polymer in theseembodiments encompasses maleic anhydride repeat units of formula (IIA)where one of R₇ and R₈ is hydrogen. Accordingly, the ring opened maleicanhydride repeat unit may be partially hydrolyzed to mono-carboxylicacid (i.e., one of R₇ and R₈ is hydrogen) or fully hydrolyzed todi-carboxylic acid (i.e., both R₇ and R₈ are hydrogen). The amount offree acid present can be tailored by controlling the degree ofesterification with an alcohol. Thus in one of the embodiments theamount of diacid present in the maleic anhydride repeat units of formula(IIA) is from about 0 mole percent to about 100 mole percent; in someother embodiments it is from about 20 mole percent to about 80 molepercent; in some other embodiments it is from about 40 mole percent toabout 60 mole percent; and in some other embodiments it is from about 45mole percent to about 55 mole percent. That is to say, when 50 molepercent of the repeat unit of formula (IIA) is diacid, the remainingportions of the repeat units are esterified, thus portions of the repeatunits may be mono-esterified or di-esterified to give a cumulative totalof 50% of the repeat units to be esterified.

Accordingly, the polymers employed in the compositions of this inventionare therefore generally formed from the hydrolysis of the polymerscontaining the repeat units of formula (IA) and formula (IIB) (COMA),which after hydrolysis results in ring-opened polymers containinggenerally the repeat units of formula (IA) and (IIA), the ROMA polymers.The COMA and ROMA polymers as employed in this invention generallyexhibit a weight average molecular weight (M_(w)) of at least about2,000. In another embodiment, the polymer of this invention has a M_(w)of at least about 6,000. In yet another embodiment, the polymer of thisinvention has a M_(w) of at least about 10,000. In some otherembodiments, the polymer of this invention has a M_(w) of at least about25,000. In some other embodiments, the polymer of this invention has aM_(w) higher than 25,000. The weight average molecular weight (M_(w)) ofthe polymer can be determined by any of the known techniques, such asfor example, by gel permeation chromatography (GPC) equipped withsuitable detector and calibration standards, such as differentialrefractive index detector calibrated with narrow-distributionpolystyrene standards.

Accordingly, any of the copolymers, terpolymers, tetrapolymers withinthe scope of the definition provided herein can be employed to form thecompositions of this invention. Exemplary polymers without anylimitations maybe enumerated as follows:

a copolymer of 5-phenethylbicyclo[2.2.1]hept-2-ene (PENB) and maleicanhydride in which maleic anhydride repeating unit is ring opened withmethanol (50:50 molar ratio);

a copolymer of 5-phenethylbicyclo[2.2.1]hept-2-ene (PENB) and maleicanhydride in which maleic anhydride repeating unit is ring opened withethanol (50:50 molar ratio); and

a copolymer of 5-phenethylbicyclo[2.2.1]hept-2-ene (PENB) and maleicanhydride in which maleic anhydride repeating unit is ring opened withn-butanol (50:50 molar ratio).

As mentioned above, the polymer compositions of this invention furthercontains a photoacid generator (PAG). Any of the PAGs known to oneskilled in the art which would bring about the desired results asfurther discussed herein can be employed in the composition of thisinvention. Broadly speaking, the PAG that can be employed in thisinvention is a nucleophilic halogenides (e.g., diphenyliodonium salt,diphenylfluoronium salt) and complex metal halide anions (e.g.,triphenylsulfonium salts). Exemplary PAGs without any limitationinclude, (p-isopropylphenyl)(p-methylphenyl)-iodoniumtetrakis(pentafluorophenyl) borate (DPI-TPFPB), available commerciallyunder the trade name RHODORSIL™ Photoinitiator 2074 from Rhodia, Inc.;(2-(4-methoxynaphthalen-1-yl)-2-oxoethyl)dimethylsulfoniumtetrakis(perfluorophenyl)borate (MNDS-TPFPB), available commerciallyunder the trade name TAG 382 from Toyo Inc.;tris(4-tert-butyl)phenyl)sulfonium tetrakis-(pentafluorophenyl)borate(TTBPS-TPFPB); tris(4-tert-butyl)phenyl)sulfonium hexafluorophosphate(TTBPS-HFP); triphenylsulfonium triflate (TPS-Tf); triazine (TAZ-101);triphenylsulfonium hexafluoroantimonate (TPS-103); triphenylsulfoniumbis(perfluoromethanesulfonyl) imide (TPS-N1); di-(p-t-butyl)phenyliodonium bis(perfluoromethanesulfonyl) imide (DTBPI-N1); potassiumtris(trifluoromethanesulfonyl) methanide, commercially available fromSynquest Laboratories; di-(p-t-butylphenyl)iodoniumtris(trifluoromethanesulfonyl)methanide (DTBPI-Cl); diphenyliodoniumhexafluorophosphate, diphenyliodonium hexafluorostibate,bis(4-(tert-butyl)phenyl)iodonium hexafluorophosphate,bis(4-(tert-butyl)phenyl)iodonium hexafluorostibate (DTBPI-Tf),diphenyliodonium trifluoromethanesulfonate, diphenyliodonium1,1,2,2,3,3,4,4,4-nonafluorobutane-1-sulfonate;bis(4-(tert-butyl)phenyl)iodonium trifluoromethanesulfonate; andbis(4-(tert-butyl)phenyl)iodonium1,1,2,2,3,3,4,4,4-nonafluorobutane-1-sulfonate; and combinationsthereof.

In one of the embodiments of this invention the PAGs employed are thefollowing:

As further noted above, the compositions of this invention also includea base. Generally, any of the bases that would bring about the desirableresults to form the photopatternable compositions can be employedherein. Although many different varieties of bases can be used, it hasbeen advantageously found that the bases, which are solid at ambientconditions exhibiting higher than 100° C. melting point are moresuitable. That is, solid bases having lower vapor pressure andoligomeric amines are suitable, among various other known bases. Otherbases which can provide good quality films and retain thermo-mechanicalproperties are also suitable.

Illustrative examples of such a base, without any limitation may beenumerated as follows:

a compound of formula (III):

wherein

R₉ and R₁₀ are the same or different and each independently of oneanother is selected from the group consisting of hydrogen, linear orbranched (C₁-C₁₆)alkyl, (C₆-C₁₀)aryl, (C₆-C₁₀)aryl(C₁-C₃)alkyl, hydroxy,halogen, linear or branched (C₁-C₁₂)alkoxy and (C₆-C₁₀)aryloxy;

a compound of the formula (IV):H₂N—R₁₂—(O(CH₂)_(d))_(e)—OR₁₁  (IV)

wherein

d is an integer from 1 to 4;

e is an integer from 5 to 50;

R₁₁ is selected from the group consisting of methyl, ethyl, linear orbranched (C₃-C₆)alkyl, (C₁-C₆)alkoxy and (C₁-C₆)alkoxy(C₁-C₄)alkyl; and

R₁₂ is substituted or unsubstituted (C₁-C₄)alkylene; and

a compound of the formula (V):

wherein

f is an integer from 25 to 100;

R₁₃ is selected from the group consisting of methyl, ethyl, linear orbranched (C₃-C₆)alkyl; and

R₁₄ is substituted or unsubstituted (C₁-C₄)alkylene.

Specific examples of such a base can be selected from the groupconsisting of:

Advantageously, photobase generators (PBGs) are another class of baseswhich can be used in the compositions of this invention. That is, PBGgenerates a base upon exposure to suitable radiation, where thegenerated base brings about the desired result as further describedherein.

Accordingly, such examples of PBGs include without any limitationvarious carbamates that decompose upon exposure to suitable radiationreleasing an amine, and various amine derivatives and suitable aminesalts, among others. Other PBGs that can be employed include acarboxylic acid or a functional equivalent derivative thereof of anamine or its equivalent, which when exposed to a suitable radiationdecomposes to release the free base. All of such compounds as singlecomponent or mixtures in any combination thereof can be used in thecomposition of this invention.

More specifically, the following PBGs may be suitable for use in thecompositions of this invention, without any limitation:

a compound of formula (VI):

a compound of formula (VII):

a compound of formula (VIII):

a compound of formula (IXA), (IXB) and (IXC):

wherein

R₁₅, R₁₆ and R₁₇ are the same or different and each independently of oneanother is selected from the group consisting of hydrogen, linear orbranched (C₁-C₁₆)alkyl, (C₆-C₁₀)aryl, (C₆-C₁₀)aryl(C₁-C₃)alkyl, hydroxy,halogen, linear or branched (C₁-C₁₂)alkoxy and (C₆-C₁₀)aryloxy; and

R₁₈ and R₁₉ each independently of one another selected from the groupconsisting of hydrogen, linear or branched (C₁-C₈)alkyl and(C₆-C₁₀)aryl; or

R₁₈ and R₁₉ taken together with the nitrogen atom to which they areattached form a 5 to 7 membered monocyclic ring or 6 to 12 memberedbicyclic ring, said rings optionally containing one or more additionalheteroatoms selected from O and N, and said rings optionally substitutedwith linear or branched (C₁-C₈)alkyl, (C₆-C₁₀)aryl, halogen, hydroxy,linear or branched (C₁-C₈)alkoxy and (C₆-C₁₀)aryloxy.

In one embodiment the PBG that is employed in the composition of thisinvention is selected from the group consisting of:

a compound of formula (VI):

and

a compound of formula (VIII):

Wherein,

R₁₅, R₁₆ and R₁₇ are the same or different and each independently of oneanother is selected from the group consisting of hydrogen, methyl,ethyl, n-propyl, iso-propyl, n-butyl and phenyl; and

R₁₈ and R₁₉ each independently of one another selected from the groupconsisting of hydrogen, methyl, ethyl, n-propyl, iso-propyl and n-butyl;or

R₁₈ and R₁₉ taken together with the nitrogen atom to which they areattached form a pyridine or pyrimidinyl ring.

Exemplary PBGs without any limitation that can used in the compositionsof this invention are selected from the group consisting of:

Surprisingly, it has now been found that by employing a suitablecombination of one or more PAGs as described herein and one or more baseas described herein, it is now possible to form a composition which whenimage-wise exposed to a suitable actinic radiation forms high resolutionimages. This is presumably due to the fact that the exposed regionsforms an acid from the PAG, which is neutralized by the base present inthe composition (and/or formed by a PBG after exposure), thus increasingthe dissolution rate (DR) of the exposed regions even after postexposure bake (PEB). On the other hand, in the unexposed regions thebase present in the composition seem to facilitate the ring closure ofthe maleic anhydride repeat units (and/or facilitate a reaction betweencarboxylic acid moiety from the polymer and an epoxy cross-linkerincorporated into the composition as disclosed herein), thustransforming the ROMA polymers into COMA polymers (and/or cross-linkedesters when an epoxy cross-linker is present) thereby lowering thedissolution rate (DR) of the unexposed region, thus providing anenhanced dissolution contrast between the exposed and unexposed regionsresulting in high resolution images. This is further described in SchemeI.

Accordingly, the compositions of this invention are capable of formingfilms useful as self-imagable layers in the manufacture ofmicroelectronic and optoelectronic devices. That is to say that whenimage-wise exposed to actinic radiation, such layers (or films) can bedeveloped to form a patterned film, where such pattern is reflective ofthe image through which the film was exposed.

In this manner, structures can be provided that are, or are to become, apart of such microelectronic and/or optoelectronic devices. For example,such films may be useful as low-K dielectric layers in liquid crystaldisplays or in microelectronic devices. It will be noted that suchexamples are only a few of the many uses for such a self-imagable film,and such examples do not serve to limit the scope of such films or thepolymers and polymer compositions that are used to form them.

Advantageously, it has now been found that polymer compositions of thisinvention provide several desirable properties especially when comparedto several of the polymers reported in the literature for similarapplications. For instance, it has been observed that several of thestyrene-maleic anhydride copolymers exhibit very high dark field loss(DFL) making them less desirable for positive tone (PT) applications. Asused herein, the term DFL or the unexposed area film thickness loss is ameasure of the film thickness loss after image-wise exposure to suitableactinic radiation and developing in a suitable developer. That is, thepolymer compositions of this invention are cast into films, the filmthicknesses before and after development in an unexposed region of thefilm are measured and reported as percent loss of the film thickness inareas of the film that was not exposed to the radiation. Generally,higher the percent of DFL, poorer the performance of the polymercomposition, which means that the unexposed areas of the film are moresusceptible to the developed and thus dissolves in the developer. Inaddition, the measured DFL also depends on the developed time employed.Generally, longer the develop time higher the DFL.

Surprisingly, the compositions of this invention exhibit very low DFL inthat the unexposed area of the film is not lost even at higher developtime. Accordingly, in some embodiments of this invention the DFL of thecompositions may be less than about 20 percent; in some otherembodiments DFL can be less than 25 percent; and in some otherembodiments the DFL may be in the range of from about 0 percent to 30percent. At the same time the develop time for the compositions of thisinvention can generally range from about 10 seconds to about 80 seconds;in some other embodiments the develop time can range from about 20seconds to about 60 seconds; and in some other embodiments the developtime can range from about 30 seconds to about 40 seconds.

In addition, advantageously it has also been found that the compositionsof this invention exhibit excellent dissolution rate in the developingsolvent, such as for example, aqueous based alkali developer, includingtetramethylammonium hydroxide (TMAH). This can further be tailored basedon the molar content of the free carboxylic acid group present in themaleic anhydride repeat units of formula (IIA) in the polymer.Generally, it has now been found that by judicious selection of themolar ratio of ring opened maleic anhydride repeat units it is nowpossible to control the dissolution rate of the composition of thisinvention to the desirable range. Furthermore, the compositions of thisinvention retain much needed lithographic resolution, photospeed andhigh degree of chemical resistance, among various other desirableproperties.

In addition, various other additives/components can be added to thecomposition of this invention, which is used for the formation of thephotoimagable layer such that its mechanical and other properties can betailored as desired. Also, other additives can be used to alter theprocessability, which include increase the stability of the polymer tothermal and/or light radiation. In this regard, the additives caninclude, but are not limited to, crosslinkers, photosensitizers,antioxidants, adhesion promoters, surfactants, thermal acid and/orthermal base generator, and the like. Any of these additives can be usedas a mixture in any combination thereof.

As summarized in Scheme I above, surprisingly, it has now been foundthat employing suitable crosslinking compound it is now possible toimprove quality of the images formed from the compositions of thisinvention. That is, by employing a suitable crosslinker such as an epoxycompound it is now possible to further decrease the dissolution rate ofthe unexposed areas thus resulting in very high resolution images asfurther illustrated by specific examples that follow. Any of thecrosslinking compounds known in the art that would bring about such aneffect can be employed to form the compositions of this invention, suchas for example epoxy compounds. Exemplary epoxies and othercross-linking additives, as mentioned above, include, but are notlimited to, bisphenol A epoxy resin (LX-01—where n=1 to 2, DaisoChemical Co., Ltd., Osaka, Japan),2,2′-((((1-(4-(2-(4-(oxiran-2-ylmethoxy)phenyl)propan-2-yl)phenyl)ethane-1,1-diyl)bis(4,1-phenylene))bis(oxy))bis(methylene))bis(oxirane)(Techmore VG3101L—Mitsui Chemical Inc., also available under thetradename EPON™ 828 from Momentive Specialty Chemicals Inc.),trimethylolpropane triglycidylether (TMPTGE—CVC Specialty Chemicals,Inc.),1,1,3,3,5,5-hexamethyl-1,5-bis(3-(oxiran-2-ylmethoxy)propyl)trisiloxane(DMS-E09—Gelest, Inc.), liquid epoxy resins (D.E.R.™ 732, where n=8 to10, and D.E.R.™ 736, where n=4 to 6—both from Dow Chemical Company),bis(4-(oxiran-2-ylmethoxy)phenyl)methane (EPON™ 862, Hexion SpecialtyChemicals, Inc.), triglycidyl ether of poly(oxypropylene)epoxide etherof glycerol (commercially available as Heloxy 84 or GE-36 from MomentiveSpecialty Chemicals Inc.), 2-((4-(tert-butyl)phenoxy)methyl)oxirane(commercially available as Heloxy 65 from Momentive Specialty ChemicalsInc.) and silicone modified epoxy compound (commercially available asBY16-115 from Toray-Dow Corning Silicone Co., Ltd.) as shown below:

D.E.R.™ 732, where n=8 to 10 and D.E.R.™ 736, where n=4 to 6

-   -   triglycidyl ether of poly(oxypropylene)epoxide ether of        glycerol, commercially available as Heloxy 84 or GE-36 from        Momentive Specialty Chemicals Inc.;

-   -   2-((4-(tert-butyl)phenoxy)methyl)oxirane, commercially available        as Heloxy 65 from Momentive Specialty Chemicals Inc.; and

-   -   Silicone modified epoxy compound commercially available as        BY16-115 from Toray-Dow Corning Silicone Co., Ltd.

Still other exemplary epoxy resins or cross-linking additives include,among others Araldite MT0163 and Araldite CY179 (manufactured by CibaGeigy); and EHPE-3150, Epolite GT300 and (manufactured by DaicelChemical).

In one embodiment of the composition of this invention the epoxies thatcan be used in the composition of this invention without any limitationis selected from the group consisting of:

triglycidyl ether of poly(oxypropylene)epoxide ether of glycerol;

trimethylolpropane triglycidylether;

bisphenol A epichlorohydrin based epoxy resin;

polypropylene glycol epichlorohydrin based epoxy resin (D.E.R.™ 732);

bis(4-(oxiran-2-ylmethoxy)phenyl)methane (EPON 862);

glycidyl ether of para-tertiary butyl phenol (Heloxy 65);

polyethylene glycol diglycidyl ether (PEGDGE); and

polypropylene glycol diglycidyl ether (PPGDGE);

and a mixture in any combination thereof.

The amount of epoxy compound employed may vary depending upon theintended result. For example, the amount can vary generally from about 0to 60 parts by weight of the polymer and typically from about 2 to about30 parts by weight, although other advantageous amounts of suchmaterials are also appropriate and within the scope of the presentinvention. In addition, one or more different types of epoxy compoundsas enumerated herein can be used in the composition of this inventionand the amounts of each can thus be varied as needed.

Advantageously, as noted, it has now been found that judicious selectionof the epoxy compound in the compositions of this invention may offercertain unexpected benefits. For instance, it has now been found thatepoxy compounds having certain desirable epoxy equivalent weight and LogP offers certain surprising benefits. As used herein “Log P” is ameasure of the partition-coefficient (P), that is, the ratio ofconcentrations of a compound in a mixture of two immiscible phases atequilibrium (water and 1-octanol). Generally, lower the Log P valuehigher the miscibility of such an epoxy compound in water. Such benefitsinclude, among other things, improved DFL properties and thermal reflowproperties. These features become more apparent from the specificexamples that follow. It should further be noted that various benefitsobtained from this invention depends on many factors as alreadydescribed herein and some of which may be readily appreciated by one ofskill in the art. Accordingly, in some embodiments the photosensitivecompositions of this invention contains an epoxy compound having anepoxy equivalent weight higher than about 200. In other embodiments suchepoxy equivalent weight may range from about 200 to 400 or higher.Further, Log P values of such epoxy compounds may be in the range offrom about −0.3 to about −0.8; in other embodiments such Log P valuesare from about −0.4 to about −0.6. In some embodiments the epoxycompound is having an equivalent weight of about 300 to 400 and Log P ofabout −0.3 to −0.4.

It will be understood that exemplary embodiments of the presentinvention, can include other suitable components and/or materials suchas are necessary for formulating and using the polymer compositions inaccordance with the present invention. Such other suitable componentsand/or materials include one or more components selected from sensitizercomponents, solvents, catalyst scavengers, stabilizers, reactivediluents, and the like.

The polymer compositions in accordance with the present invention mayfurther contain optional components as may be useful for the purpose ofimproving properties of both the composition and the resulting layer,for example the sensitivity of the composition to a desired wavelengthof exposure radiation. Examples of such optional components includevarious additives such as a dissolution promoter, a surfactant, a silanecoupling agent, a leveling agent, an antioxidant, a fire retardant, aplasticizer, a crosslinking agent or the like. Such additives include,but are not limited to, bisphenol A and 5-norbornene-2,3-dicarboxylicacid as a dissolution promoter, a silicone surfactant such as TSF4452(Toshiba Silicone Co., Ltd) or any other suitable surfactant such asMegaface F-556, a nonionic or anionic fluorinated oligomer withhydrophilic and lipophilic group from DIC Corp., a silane coupling agentsuch as γ-aminopropyl triethoxysilane, a leveling agent, such asγ-(methacryloyloxy propyl) trimethoxysilane, antioxidants such aspentaerythritoltetrakis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate) (IRGANOX™ 1010from BASF), 3,5-bis(1,1-dimethylethyl)-4-hydroxy-octadecyl esterbenzenepropanoic acid (IRGANOX™ 1076 from BASF) and thiodiethylenebis[3-(3,5-di-tert.-butyl-4-hydroxy-phenyl)propionate] (IRGANOX™ 1035from BASF), a fire retardant such as a trialkyl phosphate or otherorganic phosphoric compound and a plasticizer such as, poly(propyleneglycol).

In addition, various other additives/components can be added to thecomposition of this invention, which is used for the formation of thephotoimagable layer such that its mechanical and other properties can betailored as desired. Also, other additives can be used to alter theprocessability, which include increase the stability of the polymer tothermal and/or light radiation. In this regard, the additives caninclude, but are not limited to, crosslinking agents, adhesionpromoters, and the like. Non-limiting examples of such compounds areselected from the group consisting of the following, commerciallyavailable materials are indicated by such commercial names.

-   -   trimethoxy(3-(oxiran-2-ylmethoxy)propyl)silane, also commonly        known as 3-glycidoxypropyl trimethoxysilane (KBM-403E from        Shin-Etsu Chemical Co., Ltd.);

-   -   triethoxy(3-(oxiran-2-ylmethoxy)propyl)silane, also commonly        known as 3-glycidoxypropyl triethoxysilane (KBE-403 from        Shin-Etsu Chemical Co., Ltd.);

In the embodiments of the present invention, these components aregenerally dissolved in a solvent and prepared into a varnish form to beused. As a solvent, there may be used N-methyl-2-pyrrolidone (NMP),γ-butyrolactone (GBL), N,N-dimethylacetamide (DMAc), dimethylsulfoxide(DMSO), diethyleneglycol dimethyl ether, diethyleneglycol diethylether,diethyleneglycol dibutylether, propyleneglycol monomethylether (PGME),dipropylene glycol monomethylether, propyleneglycol monomethyletheracetate (PGMEA), methyl lactate, ethyl lactate, butyl lactate, methylethyl ketone (MEK), methyl amyl ketone (MAK), cyclohexanone,tetrahydrofuran, methyl-1,3-butyleneglycolacetate,1,3-butyleneglycol-3-monomethylether, methyl pyruvate, ethyl pyruvate,methyl-3-methoxypropionate or the like. They may be used solely or mixedby optionally selecting two or more kinds.

In one embodiment of the composition of this invention, the solvent usedin forming the composition is selected from the group consisting ofpropyleneglycol monomethylether acetate (PGMEA), gamma-butyrolactone(GBL) and N-methylpyrrolidone (NMP) and a mixture in any combinationthereof.

As mentioned above, some embodiments of the present invention encompassstructures, such as optoelectronic structures, which include at leastone self-imagable layer formed from a film of a polymer compositionembodiment in accordance with the present invention.

The aforementioned structure embodiments of the present invention arereadily formed by first casting or applying a polymer composition overan appropriate substrate to form a layer or a film thereof, then heatingthe substrate to an appropriate temperature for an appropriate time,where such time and temperature are sufficient to remove essentially allof the casting solvent of such composition. After such first heating,the layer is image-wise exposed to an appropriate wavelength of actinicradiation. As described hereinabove, the aforementioned image-wiseexposure causes the PAG contained in exposed portions of the layer toundergo a chemical reaction to form a free acid that enhances thedissolution rate of such exposed portions to an aqueous base solution(generally a solution of tetramethylammonium hydroxide (TMAH)). In thismanner, such exposed portions are removed and unexposed portions remain.Next a second heating is performed to cause ring closure of the portionsof the polymer and/or cross-linking with the epoxy additive, if present,thus essentially “curing” the polymer of such unexposed portions to forman aforementioned structure embodiment of the present invention.

It should be noted again that the second heating step, post exposurebake (PEB) is performed for the imaged and developed layer. In this stepof second heating, the thermal curing of the polymer layer can beachieved with the added additives, such as epoxies and/or othercrosslinking agents as described herein.

Accordingly, there is further provided a cured product obtained bycuring the composition of this invention as described herein. In afurther embodiment of this invention there is also provided anoptoelectronic or microelectronic device encompassing the cured productof this invention, which is having a dielectric constant of 3.2 or lessat 1 MHz.

The following examples, without being limiting in nature, illustratemethods for making composition embodiments in accordance with thepresent invention.

It should further be noted that the following examples are detaileddescriptions of methods of preparation and use of certaincompounds/monomers, polymers and compositions of the present invention.The detailed preparations fall within the scope of, and serve toexemplify, the more generally described methods of preparation set forthabove. The examples are presented for illustrative purposes only, andare not intended as a restriction on the scope of the invention. As usedin the examples and throughout the specification the ratio of monomer tocatalyst is based on a mole to mole basis.

EXAMPLES (GENERAL)

The following definitions have been used in the Examples that followunless otherwise indicated:

PENB: 5-phenethylbicyclo[2.2.1]hept-2-ene; MA: maleic anhydride; PBG-1:Irgacure369—2-benzyl-2-(dimethylamino)-1-(4-morpholinophenyl)butan-1-one; PBG-2:WPBG-140—1-(anthraquinon-2-yl)ethyl imidazolecarboxylate; Base-1:1-phenyl-2-(imidazol-1H-yl)ethanone; Base-2:O-(2-aminopropyl)-O′-(2-methoxyethyl) polypropyleneglycol; Base-3: amineterminated poly(N-isopropylacrylamide); PAG-1:GSID26-A—bis(4-((4-acetylphenyl)thio)phenyl)(4-(phenylthio)cyclohexyl)sulfoniumtris((trifluoromethyl)sulfonyl)methanide; PAG-2:1,3-dioxo-1H-benzo[de]isoquinolin-2(3H)-yl trifluoromethanesulfonate;PAG-3: 1,3-dioxo-1H-benzo[de]isoquinolin-2(3H)-yl1,1,2,2,3,3,4,4,4-nonafluorobutane-1-sulfonate; THF: tetrahydrofuran;EtOAc: ethyl acetate; MeOH: methanol; NMP: N-methyl-2-pyrrolidone;PGMEA: propyleneglycol monomethylether acetate; TMPTGE:trimethylolpropane triglycidylether; SIT-7908.0:diethoxy(propoxy)(3-thiocyanatopropyl)silane; Si-75:((triethoxysilyl)propyl)disulfide; KBM-403E: 3-glycidoxypropyltrimethoxysilane; GE-36: triglycidyl ether of poly(oxypropylene)epoxideether of glycerol; Naugard-445: bis(4-(2-phenylpropan-2-yl)phenyl)amine;Megaface F-556: fluorine based oligomer with hydrophilic and lipophilicgroup from DIC Corp.; HPLC: high performance liquid chromatography; GPC:gel permeation chromatography; M_(w): weight average molecular weight;M_(n): number average molecular weight; PDI: polydispersity index; pphr:parts per hundred resin; FT-IR: Fourier transform-infrared; NMR: nuclearmagnetic resonance; TGA: thermogravimetric analysis.

Polymers

The polymers used to form the photosensitive compositions of thisinvention are generally known in the literature and are prepared inaccordance with the well-known literature procedures. See for example,the U.S. Pat. No. 8,715,900 for all synthetic procedures related to ROMApolymers used to form the formulations of this invention.

Photoimagable Compositions

The following examples illustrate formation of the various compositionsof this invention containing a polymer, photo-acid generator, photo-basegenerator and/or base with a variety of other components/additives asdescribed herein.

Example 1

A fully ring opened copolymer (ROMA) having the monomer composition of50:50 molar ratio of PENB/MA ring opened with methanol (M_(w) 8,700 andPDI 2.0, having substantially the repeat units of formula (IIA) where R₇is methyl and R₈ is hydrogen) (100 parts resin) was dissolved in GBL(150 parts) having the specific amounts of additives, expressed as partsper hundred resin (pphr), PAG-2 (2 pphr) as a photo-acid generator,Base-1 (0.5 pphr) as a base additive, Base-3 (15 pphr) as a baseadditive, KBM-403E (3 pphr) as the adhesion promoter and GBL (300 pphr)were mixed in an appropriately sized amber HDPE bottle. The mixture wasrolled for 18 hours to produce a homogeneous solution. Particlecontamination was removed by filtering the polymer solution through a 1Lm pore polytetrafluoroethylene (PTFE) disc filter, the filtered polymersolution was collected in a low particle HDPE amber bottle and theresulting solution stored at 5° C.

Examples 2-5

In Examples 2-5, the procedures of Example 1 was substantially repeatedexcept that TMPTGE (30 pphr) as a crosslinking agent was added to thesecompositions, and in addition the following modifications were made.PAG-2 was replaced with PAG-3 (3 pphr) for Example 3, with PAG-4 (3pphr) for Example 4 and PAG-5 (3 pphr) for Example 5. The mixture thusformed in each of these Examples was rolled for 18 hours to produce ahomogeneous solution. Particle contamination was removed by filteringthe polymer solution through a 1 μm pore polytetrafluoroethylene (PTFE)disc filter, the filtered polymer solution was collected in a lowparticle HDPE amber bottle and the resulting solution stored at 5° C.

Example 6

A fully ring opened, ROMA, copolymer having the monomer composition of50:50 molar ratio of PENB/MA ring opened with methanol (M_(w) 8,600 andPDI 1.9, having substantially the repeat units of formula (IIA) where R₇is methyl and R₈ is hydrogen) (100 parts resin) was dissolved in PGMEA(800 parts) having the specific amounts of additives, expressed as partsper hundred resin (pphr), PAG-1 (5 pphr) as a photo-acid generator,PBG-1 (5 pphr) as a photo-base generator, TMPTGE (40 pphr) as acrosslinking agent, KBM-403E (3 pphr) as the adhesion promoter andMegaface F-556 (0.3 pphr) as a nonionic surfactant were mixed in anappropriately sized amber HDPE bottle. The mixture was rolled for 18hours to produce a homogeneous solution. Particle contamination wasremoved by filtering the polymer solution through a 0.2 μm porepolytetrafluoroethylene (PTFE) disc filter, the filtered polymersolution was collected in a low particle HDPE amber bottle and theresulting solution stored at 5° C.

Example 7

The procedures of Example 6 was substantially repeated in this Example 7except that PBG-2 was used instead of PBG-1.

Example 8

A fully ring opened, ROMA, copolymer having the monomer composition of50:50 molar ratio of PENB/MA ring opened with methanol (M_(w) 8,600 andPDI 1.9, having substantially the repeat units of formula (IIA) where R₇is methyl and R₈ is hydrogen) (100 parts resin) was dissolved in PGMEA(800 parts) having the specific amounts of additives, expressed as partsper hundred resin (pphr), PAG-1 (5 pphr) as a photo-acid generator,Base-1 (5 pphr) as a base additive, TMPTGE (40 pphr) as a crosslinkingagent, KBM-403E (3 pphr) as the adhesion promoter and Megaface F-556(0.3 pphr) as a nonionic surfactant were mixed in an appropriately sizedamber HDPE bottle. The mixture was rolled for 18 hours to produce ahomogeneous solution. Particle contamination was removed by filteringthe polymer solution through a 0.2 μm pore polytetrafluoroethylene(PTFE) disc filter, the filtered polymer solution was collected in a lowparticle HDPE amber bottle and the resulting solution stored at 5° C.

Example 9

A fully ring opened, ROMA, copolymer having the monomer composition of50:50 molar ratio of PENB/MA ring opened with methanol (M_(w) 8,700 andPDI 2.0, having substantially the repeat units of formula (IIA) where R₇is methyl and R₈ is hydrogen) (100 parts resin) was dissolved in GBL(150 parts) having the specific amounts of additives, expressed as partsper hundred resin (pphr), PAG-1 (4.7 pphr) as a photo-acid generator,Base-2 (2.5 pphr) as a base additive, TMPTGE (20 pphr) as a crosslinkingagent, GE-36 (40 pphr) as a cross linking agent, SIT 7908.0 (3 pphr),Naugard 445 (5 pphr), AO-80 (5 pphr), Megaface F-556 (0.3 pphr) and GBL(100 pphr) were mixed in an appropriately sized amber HDPE bottle. Themixture was rolled for 18 hours to produce a homogeneous solution.Particle contamination was removed by filtering the polymer solutionthrough a 1 μm pore polytetrafluoroethylene (PTFE) disc filter, thefiltered polymer solution was collected in a low particle HDPE amberbottle and the resulting solution stored at 5° C.

Example 10

A fully ring opened, ROMA, copolymer having the monomer composition of50:50 molar ratio of PENB/MA ring opened with methanol (M_(w) 8,700 andPDI 2.0, having substantially the repeat units of formula (IIA) where R₇is methyl and R₈ is hydrogen) (100 parts resin) was dissolved in GBL(150 parts) having the specific amounts of additives, expressed as partsper hundred resin (pphr), PAG-1 (4 pphr) as a photo-acid generator,Base-1 (0.25 pphr) as a base additive, Base-3 (16 pphr) as a baseadditive, TMPTGE (20 pphr) as a crosslinking agent, GE-36 (40 pphr) as across linking agent, SIT 7908.0 (3 pphr), Naugard 445 (5 pphr), AO-80 (5pphr) and Megaface F-556 (0.3 pphr) were mixed in an appropriately sizedamber HDPE bottle. The mixture was rolled for 18 hours to produce ahomogeneous solution. Particle contamination was removed by filteringthe polymer solution through a 1 μm pore polytetrafluoroethylene (PTFE)disc filter, the filtered polymer solution was collected in a lowparticle HDPE amber bottle and the resulting solution stored at 5° C.

Examples 11-16 Dissolution Rate (DR) and FT-IR Measurements

The following Examples illustrate the dissolution rate (DR) measurementsof the compositions of Examples 1-10. The compositions of Examples 1 and2 were spin coated on a 4-inch thermal oxide silicon wafer at 500 rpmfor 30 seconds and post apply baked (PAB) at 110° C. for 3 minutes toform a film of the respective composition from each of Examples 1-10.The wafers were cleaved into two parts. One part of the film was firstexposed to a blanket exposure dose of 1 J/cm² (EXD) and post exposurebaked (PEB) at 130° C. for 5 minutes. The other part was baked at 130°C. for 5 minutes to mimic the PEB without the blanket exposure. The filmthicknesses of these films were measured and found to range from 2-4 μm.These were immersed in 2.38 wt. % TMAH and the film thicknesses (FT)were measured again after 5-40 second time intervals. The dissolutionrates (DR) in 2.38 wt. % TMAH as nm/sec were estimated as the slope ofthe film thickness vs. time plots. Similarly a solution of the polymerin GBL used in Example 1 was spin coated on a 4-inch thermal oxidesilicon wafer at 500 rpm for 30 seconds and post apply baked (PAB) at110° C. for 3 minutes followed by a second bake at 130° C./5 minutes tomimic the PEB. The dissolution rate of this film having film thicknessof 2.03 μm was estimated as 63 nm/sec using the same procedure asdescribed above.

FT-IR Measurements

Films of composition Examples 1 and 2 were prepared using the samemethod as described above for DR measurements except no TMAH immersionwas conducted for IR measurements (Examples 13 to 16). Also included inthis study was a solution of the polymer alone (Examples 11 and 12).Small amounts of the films were scraped out and their FT-IR spectra weretaken on a diamond cell. FT-IR peaks observed at about 1853 cm⁻¹ and1774 cm⁻¹ are characteristic of cyclic anhydrides (structure IIB) and apeak at about 1735 cm⁻¹ is characteristic for carbonyl group ofcarboxylic acid and a carboxylic acid ester (structure IIA where R₇ ismethyl and R₈ is hydrogen). The peak heights representing the cyclicanhydride at about 1774 cm⁻¹ and the carboxylic acid and its methylester were measured from an arbitrary baseline drawn consistently forall spectra. The relative amounts of the cyclic anhydride present in thefilm were compared from the ratio of those peak heights.

The FT-IR peak ratios as a comparison for the relative presence ofcyclic anhydride and the dissolution rates of these films are summarizedin Table 1. It is evident from the data presented in Examples 11 and 12of Table 1 for the polymer solution that the incorporation of a secondbake step to mimic the PEB causes partial ring closure of acid-estergroup of the polymer to generate cyclic anhydride form (structure IIB)associated with some decrease in its dissolution rate. This effect ismore pronounced in the unexposed film using the composition of Example 1as evident in Example 13. That is, even with no exposure to light, thePEB causes more cyclization of the ring opened repeat units of formula(IIA) to anhydride form, i.e., repeat units of formula (IIB). Howeverthis effect is less prominent in the exposed areas as evident in Example14, i.e., the composition of Example 1 when exposed to an actinic lightat a dosage of 1 J/cm² lowers the extent of ring closure to form therepeat units of formula (IIB) because of the fact that the exposurecauses PAG to form a free acid which is neutralized by the base, andtherefore, there is not enough base present in the composition to affectthe ring closure to anhydride form. As a result, this facilitates adissolution rate (DR) contrast in exposed and unexposed regions of thefilm where the exposed area has a higher DR than the unexposed areaenabling positive tone imaging of these formulated films having goodresolution of images. This DR contrast is more prominent in Examples 15and 16 where in addition to a PAG and base additives a tri-functionalepoxy cross-linker is also present in the composition (i.e., compositionof Example 2).

TABLE 1 Composition EXD Peak Ratio Example Example (1 J/cm⁻²) PEB (1774cm⁻¹/1735 cm⁻¹) DR (nm/sec) 11 Only PENB/MA, No No 0.57 84 ROMA polymer12 Only PENB/MA, No Yes 0.70 63 ROMA polymer 13 1 No Yes 0.87 19 14 1Yes Yes 0.64 56 15 2 No Yes 0.93  0 (very low) 16 2 Yes Yes 0.76 24

FIG. 1 shows the FT-IR spectra of the films obtained from Examples 15and 16. It is evident from FIG. 1 that the relative peak heights of 1774cm⁻¹ (ring closed or the anhydride peak) and 1735 cm⁻¹ (peak due tocarbonyl of the free acid, ester or the carboxylic acid crosslinked withepoxy) for film from Example 15 where the film was not exposed toradiation clearly shows more ring closure (i.e., more pronouncedanhydride peak) than the film from Example 16 where the peak due toanhydride is smaller.

As illustrated in Scheme 1 discussed hereinabove, the base additive inthe exposed regions is neutralized by the acid formed in those regionsof the film by photo conversion of the PAG. Therefore no significantchange is occurring in the exposed regions during the PEB step. However,the presence of the base additive in the unexposed regions in theabsence of any acid to neutralize it will cause the ring closure ofrepeat units of formulae (IIA) to (IIB) as evidenced by the FT-IRspectroscopic studies as discussed above, and thereby limiting theaqueous base solubility in the exposed regions. Furthermore when anepoxy cross-linker is also present in the composition the base additivemay catalyze the cross-linking of the polymer in the unexposed regions.This may cause further lowering of the aqueous base developability ofthe unexposed regions. Thus resulting in a high resolution positive toneimages, which are further illustrated by the following examples.

Photo Imaging Examples Examples 17-24

The following Examples illustrate the photo imaging capability of thecompositions of Examples 1-8. The compositions of Examples 1-8 were spincoated at a spin speed of 800 rpm for 30 seconds for compositions ofExamples 1-5 and 4500 rpm for compositions of Examples 6-8 on a 4-inchthermal oxide silicon wafer. The coated films were post apply baked(PAB) at 110° C. for compositions of Examples 1-5 and 100° C. forcompositions of Examples 6-8 on a hot plate for 3 minutes in each of theExamples. The films were then exposed using a combination of a patternedmask and a variable density mask to a broad band Hg-vapor light source(at 365 nm using a band pass filter) at an exposure dose of 1000 mJ/cm².The exposed films were post exposure baked (PEB), developed for a giventime (Dev.) with 2.38 wt. % TMAH in a puddle, rinsed with distilledwater and dried using a stream of nitrogen. The film thicknesses (FT)were measured after PAB and development. The unexposed film thicknessloss or dark field loss (DFL) was determined from the percent FT loss ofan unexposed region of the film after development. In some cases thereis a gain of the film thickness in the unexposed regions. This is due tothe swelling of the film and is denoted as positive value and thetypical loss of the film is denoted as a negative value. The formationof images (trenches, pillars and contact holes) were observed by anoptical microscope to determine the resolution capability for trenches,pillars and contact holes (CH) from their top-down images.

These imaged films were cured in an oven under nitrogen atmosphere at200° C. for 1 hour to determine their thermal flow. The thermal flow wasdeemed good for Examples 17-24 based on the observation that thefeatures remained intact after cure as observed by an opticalmicroscope.

Table 2 summarizes the observed properties for the photo imaging resultsof the films generated from compositions of Examples 1-8.

TABLE 2 Composition FT Dose PEB Dev. DFL Resolution (μm) Example Example(μm) (mJ/cm²) (° C./min) (sec) (%) Trench/pillar/CH 17 1 1.74 510 130/530 −74  3/5/3 18 2 2.15 510 135/3 150 −3  7/7/3 19 3 2.36 405 125/3 45−2  7/7/3 20 4 2.53 510 135/3 385 +9 10/10/5 21 5 2.27 327 135/3 95 −310/10/5 22 6 1.00 255 140/3 45 −6  7/15/10 23 7 1.06 405 110/2 30 +4 3/5/5 24 8 0.90 327 None 36 −32  3/7/5

Example 25

The composition of Example 9 was spin coated at a spin speed of 1000 rpmfor 30 seconds on a 4-inch thermal oxide silicon wafer. The coated filmwas post apply baked (PAB) at 120° C. on a hot plate for 3 minutes toobtain a film having a thickness of 7.89 μm. The film was then exposedusing a combination of a patterned mask and a variable density mask to abroad band Hg-vapor light source (at 365 nm using a band pass filter) atan exposure dose of 700 mJ/cm². The exposed film was post exposure baked(PEB) at 140° C. for 3 minutes on a hot plate. The film thickness afterPEB was 7.59 μm. The film was developed for 30 seconds with 2.38 wt. %TMAH in a puddle, rinsed with distilled water and dried using a streamof nitrogen. The film thicknesses (FT) after development was 3.48 μm.The unexposed film thickness loss or dark field loss (DFL) of 54% wascalculated based on film thicknesses before and after development.Trenches at a resolution of about 7 μm and contact holes at a resolutionof about 25 μm were observed by an optical microscope.

Example 26

The composition of Example 10 was spin coated at a spin speed of 2000rpm for 30 seconds on a 4-inch thermal oxide silicon wafer. The coatedfilm was post apply baked (PAB) at 120° C. on a hot plate for 3 minutesto obtain a film having a thickness of 9.55 μm. The film was thenexposed using a combination of a patterned mask and a variable densitymask to a broad band Hg-vapor light source (at 365 nm using a band passfilter) at an exposure dose of 500 mJ/cm². The exposed film was postexposure baked (PEB) at 140° C. for 5 minutes on a hot plate. The filmthickness after PEB was 9.08 μm. The film was developed for 115 secondswith 2.38 wt. % TMAH in a puddle, rinsed with distilled water and driedusing a stream of nitrogen. The film thicknesses (FT) after developmentwas 7.55 μm. The unexposed film thickness loss or dark field loss (DFL)of 17% was calculated based on film thicknesses before and afterdevelopment. FIGS. 2A and 2B show the scanning electron microscopy (SEM)micrographs of a cross section of 5 and 10 μm trenches respectively atthe exposure dose of 255 mJ/cm².

Example 27

The composition of Example 10 was spin coated at a spin speed of 1500rpm for 30 seconds on a 4-inch thermal oxide silicon wafer. The coatedfilm was post apply baked (PAB) at 120° C. on a hot plate for 3 minutesto obtain a film thickness of 13.77 μm. The film was then exposed usinga combination of a patterned mask and a variable density mask to a broadband Hg-vapor light source (at 365 nm using a band pass filter) at anexposure dose of 700 mJ/cm². The exposed film was post exposure baked(PEB) at 140° C. for 5 minutes on a hot plate. The film thickness afterPEB was 13.28 μm. The film was developed for 155 seconds with 2.38 wt. %TMAH in a puddle, rinsed with distilled water and dried using a streamof nitrogen. The film thicknesses (FT) after development was 10.67 μm.The unexposed film thickness loss or dark field loss (DFL) of 20% wascalculated based on film thicknesses before and after development. Thefilm was cured at 180° C. for 2 hours in an oven under nitrogenatmosphere. FIG. 3 shows the SEM micrograph of a cross section of 10 μmtrench after the cure step at the exposure dose of 283 mJ/cm².

Example 28

The composition of Example 10 was spin coated at a spin speed of 1100rpm for 30 seconds on a 4-inch thermal oxide silicon wafer. The coatedfilm was post apply baked (PAB) at 110° C. on a hot plate for 3 minutesto obtain a film thickness of 10.51 μm. The film was then exposed usinga patterned mask to a broad band Hg-vapor light source (at 365 nm usinga band pass filter) at an exposure dose of 500 mJ/cm². The exposed filmwas post exposure baked (PEB) at 140° C. for 6 minutes on a hot plate.The film thickness after PEB was 10.12 μm. The film was developed for 95seconds with 2.38 wt. % TMAH in a puddle, rinsed with distilled waterand dried using a stream of nitrogen. The film thicknesses (FT) afterdevelopment was 7.85 μm. The unexposed film thickness loss or dark fieldloss (DFL) of 22% was calculated based on film thicknesses before andafter development. The film was cured at 180° C. for 2 hours in an ovenunder nitrogen atmosphere. FIG. 4A shows the SEM micrograph of a crosssection of 25 μm contact holes (CH) before cure and FIG. 4B shows theSEM micrograph of a cross section of 25 μm contact holes (CH) after thecure step.

Examples 29-31 Thermomechanical Property Measurements

In three separate Examples 29-31, the composition of Example 10 was spincoated onto a 5-inch bare silicon wafers to obtain films in thethickness range from 9-12 μm. Each of these films were cured in an ovenunder nitrogen atmosphere at 180° C. for 2 hours. Then variousthermo-mechanical properties of these films were measured as summarizedin Table 3.

TABLE 3 Thermomechanical properties of formulation examples 10-12Measured Property Example 29 Example 30 Example 31 Wafer Stress (MPa) 8± 3 10 ± 1 10 ± 3 T_(g) (TMA), ° C. 106 111 108 ETB (%) 4 3 8 TensileStrength (MPa) 39 40 40 Young's Modulus (GPa) 1.8 2.1 1.8T_(d5)/T_(d50), ° C. (TGA) 293/380 293/392 295/465 ETB = elongation tobreak; T_(g) = glass transition temperature; TMA = thermomechanicalanalysis; TGA = thermogravimetric analysis; T_(d5) = temperature atwhich 5 weight percent loss of the material observed; T_(d50) =temperature at which 50 weight percent loss of the material observed.

The following Comparative Examples 1-4 are provided to show in theabsence of a PAG the composition thus formed cannot be photoimaged andin the absence of a base the composition so formed forms a negative tonephotoimagable composition.

Comparative Example 1

A fully ring opened, ROMA, copolymer having the monomer composition of50:50 molar ratio of PENB/MA ring opened with methanol (M_(w) 8,700 andPDI 2, repeat units of formula (IIA) where R₇ is methyl and R₈ ishydrogen) (100 parts resin) was dissolved in GBL (150 parts) having thespecific amounts of additives, expressed as parts per hundred resin(pphr), Base-1 (0.5 pphr) and Base-3 (15 pphr) as base additives, TMPTGE(30 pphr) as a crosslinking agent, KBM-403E (3 pphr) as the adhesionpromoter and GBL (300 pphr) were mixed in an appropriately sized amberHDPE bottle. The mixture was rolled for 18 hours to produce ahomogeneous solution. Particle contamination was removed by filteringthe polymer solution through a 1 μm pore polytetrafluoroethylene (PTFE)disc filter, the filtered polymer solution was collected in a lowparticle HDPE amber bottle and the resulting solution stored at 5° C.

Comparative Example 2

A fully ring opened, ROMA, copolymer having the monomer composition of50:50 molar ratio of PENB/MA ring opened with methanol (M_(w) 8,700 andPDI 2, repeat units of formula (IIA) where R₇ is methyl and R₈ ishydrogen) (100 parts resin) was dissolved in GBL (150 parts) having thespecific amounts of additives, expressed as parts per hundred resin(pphr), PAG-2 (2 pphr) as a photo-acid generator, TMPTGE (30 pphr) as acrosslinking agent, KBM-403E (3 pphr) as the adhesion promoter and GBL(300 pphr) were mixed in an appropriately sized amber HDPE bottle. Themixture was rolled for 18 hours to produce a homogeneous solution.Particle contamination was removed by filtering the polymer solutionthrough a 1 μm pore polytetrafluoroethylene (PTFE) disc filter, thefiltered polymer solution was collected in a low particle HDPE amberbottle and the resulting solution stored at 5° C.

Comparative Example 3

The composition of Comparative Example 1 was spin coated at a spin speedof 800 rpm for 30 seconds on a 4-inch thermal oxide silicon wafer. Thecoated film was post apply baked (PAB) at 110° C. for 3 minutes toobtain a film having film thickness of 2 μm. This film was exposed usinga combination of a patterned mask and a variable density mask to a broadband Hg-vapor light source (at 365 nm using a band pass filter) at anexposure dose of 1000 mJ/cm². The exposed film was post exposure baked(PEB) at 135° C. for 5 minutes, developed for 150 seconds with 2.38 wt.% TMAH in a puddle, rinsed with distilled water and dried using a streamof nitrogen. The film thickness (FT) after the development was 1.87 μmin unexposed regions of the film. The unexposed film thickness loss ordark field loss (DFL) of 7% was determined from the percent FT loss ofan unexposed region of the film after development. There was noformation of images observed by an optical microscope in this instancedemonstrating that the mere presence of base additives is not sufficientto affect positive tone photo imaging.

Comparative Example 4

The composition of Comparative Example 2 was spin coated at a spin speedof 800 rpm for 30 seconds on a 4-inch thermal oxide silicon wafer. Thecoated film was post apply baked (PAB) at 110° C. for 3 minutes toobtain a film having film thickness of 1.45 μm. This film was exposedusing a combination of a patterned mask and a variable density mask to abroad band Hg-vapor light source (at 365 nm using a band pass filter) atan exposure dose of 1000 mJ/cm². The exposed films were post exposurebaked (PEB) at 135° C. for 1 minute, developed for 30 seconds with 2.38wt. % TMAH in a puddle, rinsed with distilled water and dried using astream of nitrogen. The film thickness (FT) after the development waszero in unexposed regions of the film showing that the entire film hasdissolved in 2.38 wt. % TMAH. The unexposed film thickness loss or darkfield loss (DFL) of 100% can be calculated from the percent FT loss ofan unexposed region of the film after development. There was formationof negative tone images observed by an optical microscope in thisinstance demonstrating that the presence of a photo acid generator iscapable of affecting negative tone photo imaging in the absence of abase additives. The film thickness of a region exposed to 510 mJ/cm²exposure dose was 1.64 μm. The exposed film thickness loss or brightfield loss (BFL) can be calculated from the percent FT change of theexposed region of the film after development. In this instance a filmthickness gain of 12% in the region exposed to 510 mJ/cm² exposure dosewas observed.

Although the invention has been illustrated by certain of the precedingexamples, it is not to be construed as being limited thereby; butrather, the invention encompasses the generic area as hereinbeforedisclosed. Various modifications and embodiments can be made withoutdeparting from the spirit and scope thereof.

What is claimed is:
 1. A composition comprising: a polymer comprisingone or more distinct first repeating unit represented by formula (IA),each of said first repeating unit is derived from a monomer of formula(I):

wherein

represents a position at which the bonding takes place with anotherrepeat unit; m is an integer 0, 1 or 2; R₁, R₂, R₃ and R₄ independentlyrepresents hydrogen, linear or branched (C₁-C₁₆)alkyl,hydroxy(C₁-C₁₂)alkyl, perfluoro(C₁-C₁₂)alkyl, (C₃-C₁₂)cycloalkyl,(C₆-C₁₂)bicycloalkyl, (C₇-C₁₄)tricycloalkyl, (C₆-C₁₀)aryl,(C₆-C₁₀)aryl(C₁-C₃)alkyl, perfluoro(C₆-C₁₀)aryl,perfluoro(C₆-C₁₀)aryl(C₁-C₃)alkyl, (C₅-C₁₀)heteroaryl,(C₅-C₁₀)heteroaryl(C₁-C₃)alkyl, hydroxy, (C₁-C₁₂)alkoxy,(C₃-C₁₂)cycloalkoxy, (C₆-C₁₂)bicycloalkoxy, (C₇-C₁₄)tricycloalkoxy,—(CH₂)_(a)—(O—(CH₂)_(b))_(c)—O—(C₁-C₄)alkyl, where a, b and c areintegers from 1 to 4, (C₆-C₁₀)aryloxy(C₁-C₃)alkyl,(C₅-C₁₀)heteroaryloxy(C₁-C₃)alkyl, (C₆-C₁₀)aryloxy,(C₅-C₁₀)heteroaryloxy, (C₁-C₆)acyloxy and halogen; and a secondrepeating unit represented by formula (IIA), said second repeating unitis derived from a monomer of formula (II):

wherein: R₅ and R₆ independently of each other selected from hydrogenand methyl; R₇ is selected from the group consisting of methyl, ethyl,n-propyl and n-butyl; R₈ is hydrogen; a photoacid generator, which formsan acid when exposed to an actinic radiation; a base selected from thegroup consisting of: a compound of the formula (III):

wherein R₉ and R₁₀ are the same or different and each independently ofone another is selected from the group consisting of hydrogen, linear orbranched (C₁-C₁₆)alkyl, (C₆-C₁₀)aryl, (C₆-C₁₀)aryl(C₁-C₃)alkyl, hydroxy,halogen, linear or branched (C₁-C₁₂)alkoxy and (C₆-C₁₀)aryloxy; acompound of the formula (IV):H₂N—R₁₂—(O(CH₂)_(d))_(e)—OR₁₁  (IV) wherein d is an integer from 1 to 4;e is an integer from 5 to 50; R₁₁ is selected from the group consistingof methyl, ethyl, linear or branched (C₃-C₆)alkyl, (C₁-C₆)alkoxy and(C₁-C₆)alkoxy(C₁-C₄)alkyl; and R₁₂ is substituted or unsubstituted(C₁-C₄)alkylene; and a compound of the formula (V):

wherein f is an integer from 25 to 100; R₁₃ is selected from the groupconsisting of methyl, ethyl, linear or branched (C₃-C₆)alkyl; and R₁₄ issubstituted or unsubstituted (C₁-C₄)alkylene; and a carrier solvent; andwherein the base is present in a sufficient amount to neutralize theacid formed when the composition is exposed to an actinic radiation. 2.The composition according to claim 1, wherein said polymer furthercomprises a second distinct repeat unit of formula (IIB) derived from amonomer of formula (II):

wherein R₅ and R₆ are as defined in claim
 1. 3. The compositionaccording to claim 1, wherein said polymer comprises one or moredistinct repeating units of formula (IA) having: m is 0; R₁, R₂, R₃ andR₄ are independently selected from the group consisting of hydrogen,methyl, ethyl, linear or branched (C₁-C₁₂)alkyl, phenyl(C₁-C₃)alkyl,—(CH₂)_(a)—(O—(CH₂)_(b))_(c)—O—(C₁-C₄)alkyl, where a is 1 or 2, b is 2to 4 and c is 2 or
 3. 4. The composition according to claim 1, whereinsaid polymer is having R₅ and R₆ each hydrogen; and R₇ is selected fromthe group consisting of methyl and ethyl.
 5. The composition accordingto claim 1, wherein said polymer is having one or more first repeatingunit derived from a monomer selected from the group consisting of:5-hexylbicyclo[2.2.1]hept-2-ene; 5-octylbicyclo[2.2.1]hept-2-ene;5-decylbicyclo[2.2.1]hept-2-ene;5-((2-(2-methoxyethoxy)ethoxy)methyl)bicyclo[2.2.1]hept-2-ene;1-(bicyclo[2.2.1]hept-5-en-2-yl)-2,5,8,11-tetraoxadodecane;5-benzylbicyclo[2.2.1]hept-2-ene; and5-phenethylbicyclo[2.2.1]hept-2-ene.
 6. The composition according toclaim 1, wherein said polymer is having a second repeating unit derivedfrom a monomer selected from the group consisting of: maleic anhydride;2-methyl-maleic anhydride (3-methylfuran-2,5-dione); and2,3-dimethyl-maleic anhydride (3,4-dimethylfuran-2,5-dione).
 7. Thecomposition according to claim 1, wherein said polymer is selected fromthe group consisting of: a copolymer of5-phenethylbicyclo[2.2.1]hept-2-ene (PENB) and maleic anhydride in whichmaleic anhydride repeating unit is ring opened with methanol (50:50molar ratio); a copolymer of 5-phenethylbicyclo[2.2.1]hept-2-ene (PENB)and maleic anhydride in which maleic anhydride repeating unit is ringopened with ethanol (50:50 molar ratio); and a copolymer of5-phenethylbicyclo[2.2.1]hept-2-ene (PENB) and maleic anhydride in whichmaleic anhydride repeating unit is ring opened with n-butanol (50:50molar ratio).
 8. The composition according to claim 1, wherein saidphotoacid generator is selected from the group consisting of:(p-isopropylphenyl)(p-methylphenyl)-iodonium tetrakis(pentafluorophenyl)borate; (2-(4-methoxynaphthalen-1-yl)-2-oxoethyl)dimethylsulfoniumtetrakis(perfluorophenyl)borate;bis(4-((4-acetylphenyl)thio)phenyl)(4-(phenylthio)cyclohexyl)sulfoniumtris((trifluoromethyl)sulfonyl)methanide;1,3-dioxo-1H-benzo[de]isoquinolin-2(3H)-yl trifluoromethanesulfonate(NIT); and 1,3-dioxo-1H-benzo[de]isoquinolin-2(3H)-yl1,1,2,2,3,3,4,4,4-nonafluorobutane-1-sulfonate.
 9. The compositionaccording to claim 1, wherein said base is a compound of the formula(III):

wherein R₉ and R₁₀ are the same or different and each independently ofone another is selected from the group consisting of hydrogen, methyland ethyl.
 10. The composition according to claim 9, wherein said baseis:


11. The composition according to claim 1, wherein said base is acompound of the formula (IV):H₂N—R₁₂—(O(CH₂)_(d))_(e)—OR₁₁  (IV) wherein d is an integer from 1 to 3;e is 8; R₁₁ is selected from the group consisting of methyl and ethyl;R₁₂ is methyl substituted ethylene.
 12. The composition according toclaim 11, wherein said base is of the formula:

where e is 8 O-(2-aminopropyl)-O′-(2-methoxyethyl) polypropyleneglycol(APMEPPG).
 13. The composition according to claim 1, wherein said baseis (V):

wherein f is 100; R₁₃ is selected from the group consisting of methyl,ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl and tert-butyl; and R₁₄is ethylene or thioethylene.
 14. The composition according to claim 13,wherein said base is:

where f is 100 amine terminated poly(N-isopropylacrylamide).
 15. Thecomposition according to claim 1, which further comprises an epoxy resinselected from the group consisting of: triglycidyl ether ofpoly(oxypropylene)epoxide ether of glycerol; trimethylolpropanetriglycidylether; bisphenol A epichlorohydrin based epoxy resin;polypropylene glycol epichlorohydrin based epoxy resin;bis(4-(oxiran-2-ylmethoxy)phenyl)methane; glycidyl ether ofpara-tertiary butyl phenol; polyethylene glycol diglycidyl ether; andpolypropylene glycol diglycidyl ether; and a mixture in any combinationthereof.
 16. The composition according to claim 1, wherein said solventis selected form the group consisting of propyleneglycol monomethyletheracetate (PGMEA), gamma-butyrolactone (GBL) and N-methylpyrrolidone (NMP)and a mixture in any combination thereof.
 17. The composition accordingto claim 1, wherein said composition further comprises one or moreadditives selected from the group consisting of: adhesion promoters;antioxidants; surfactants; thermal acid or thermal base generator; andmixtures in any combination thereof.
 18. A process for forming a curedproduct, comprising: (i) applying the composition of claim 1 on asubstrate to form a coating film, (ii) exposing the coating film tolight through a desired pattern mask, (iii) dissolving and removing theexposed portions by developing with an alkaline developer to obtain thedesired pattern, and (iv) heating the obtained desired pattern.
 19. Acured product obtained by curing the composition of claim
 1. 20. Anoptoelectronic or microelectronic device comprising the cured product ofclaim 19, which is having a dielectric constant of 3.2 or less at 1 MHz.